Method of bonding porous metal to metal substrates

• US 8,951,465 B2
• Filed: 02/25/2013
• Issued: 02/10/2015
• Est. Priority Date: 10/08/2009
• Status: Active Grant

• Current Assignee: Biomet Manufacturing, LLC (Zimmer Biomet Holdings, Inc.)
• Original Assignee: Biomet Manufacturing, LLC (Zimmer Biomet Holdings, Inc.)
• Inventors: Gupta, Gautam
• Primary Examiner(s): Wyszomierski, George
• Assistant Examiner(s): MAI, NGOCLAN THI
• Application Number:
  US13/776,272
• Publication Number:
  US 20130177467A1
• Time in Patent Office: 715 Days
• Field of Search: 419/2, 419/8, 419/9, 419/36, 419/37, 419/48, 419/53, 419/55, 428/550, 428/555
• US Class Current: 419/8
• CPC Class Codes: A61F 2/30767 Special external or bone-contacting surface, e.g. coating for improving bone ingrowth
• CPC Class Codes: A61F 2/3094 Designing or manufacturing processes
• CPC Class Codes: A61F 2/34 Acetabular cups
• CPC Class Codes: A61F 2002/30769 madreporic
• CPC Class Codes: A61F 2002/3092 having an open-celled or open-pored structure
• CPC Class Codes: A61F 2002/30929 having at least two superposed coatings
• CPC Class Codes: A61F 2002/30967 Diffusion bonding
• CPC Class Codes: A61F 2002/30968 Sintering
• CPC Class Codes: A61L 27/04 Metals or alloys
• CPC Class Codes: A61L 27/56 Porous materials, e.g. foams or sponges
• CPC Class Codes: B22F 3/1134 Inorganic fillers carbonaceous or paper filler B22F3/1121
• CPC Class Codes: B22F 7/004 comprising at least one non-porous part
• CPC Class Codes: Y10T 428/12042 Porous component
• CPC Class Codes: Y10T 428/12076 Next to each other

Abstract

A method for preparing an implant having a porous metal component. A loose powder mixture including a biocompatible metal powder and a spacing agent is prepared and compressed onto a metal base. After being compressed, the spacing agent is removed, thereby forming a compact including a porous metal structure pressed on the metal base. The compact is sintered, forming a subassembly, which is aligned with a metal substrate portion of an implant. A metallurgical bonding process, such as diffusion bonding, is performed at the interface of the subassembly and the metal substrate to form an implant having a porous metal component.

Claims

1. A method for preparing an implant having a porous metal component, comprising:

compressing a compact having a porous metal structure onto a metal base, the porous metal structure being formed from compressed powder particles and the metal base comprising a solid metal layer of material;

sintering adjacent compressed powder particles of the porous metal structure to one another while concurrently sintering the porous metal structure to the metal base to form a subassembly;

aligning the subassembly with a metal substrate component; and

forming a metallurgical bond by maintaining a compressive force of between about 10 psi and about 30 psi along an interface between the metal base of the subassembly and the metal substrate component and diffusion bonding the solid metal layer of the metal base of the subassembly and the metal substrate component to form an implant.

2. The method of claim 1, wherein the metal substrate component comprises a metal face, and the diffusion bonding occurs at an interface between the solid metal layer and the metal face.

3. The method of claim 1, wherein compressing the compact onto the metal base comprises applying an isostatic pressing technique at ambient temperature.

4. The method of claim 1, wherein the compact comprises a biocompatible metal powder selected from the group consisting of titanium, titanium alloys, cobalt, cobalt alloys, chromium, chromium alloys, tantalum, tantalum alloys, iron alloys, stainless steel, and mixtures thereof.

5. The method of claim 1, wherein the porous metal structure and the metal base have the same chemical composition.

6. The method of claim 1, further comprising machining one or both of the porous metal structure and the metal substrate component prior to forming the metallurgical bond between the subassembly and the metal substrate component.

7. The method of claim 1, further comprising machining the implant after the diffusion bonding.

8. The method of claim 1, further comprising coating at least a surface of the implant with material selected from the group consisting of resorbable ceramics, resorbable polymers, antimicrobials, demineralized bone, blood products, stem cells, growth factors, and mixtures thereof.

9. A method for preparing an implant having a porous metal component, comprising:

aligning a subassembly comprising a porous metal structure having a non-porous solid metal backing with a metal substrate component; and

maintaining a compressive force of between about 10 psi and about 30 psi along an interface between the solid metal backing of the subassembly and the metal substrate component and diffusion bonding the solid metal backing to the metal substrate component to form an implant.

10. The method of claim 9, further comprising cooling the implant for a time period of from about 3 hours to about 20 hours in an inert atmosphere after the diffusion bonding.

11. The method of claim 9, wherein the non-porous solid metal backing has a thickness of about 0.5 mm.

12. The method of claim 9, wherein the diffusion bonding comprises maintaining a compressive force of about 20 psi at the interface.

13. The method of claim 9, wherein the metal substrate component comprises a metal face, and the diffusion bonding occurs at an interface between the solid metal backing and the metal face.

14. The method of claim 9, further comprising machining the implant after the diffusion bonding.

15. A method for preparing an implant having a porous metal component, comprising:

compressing a loose powder mixture comprising a biocompatible metal powder, a spacing agent and a non-polar liquid binder onto a metal base, the metal base comprising a solid metal layer of material taken from a solid metal block;

removing the spacing agent to form a compact having a porous metal structure pressed on the metal base;

sintering adjacent powder particles of the porous metal structure to one another while concurrently sintering the porous structure to the metal base to form a subassembly;

aligning the subassembly with a metal substrate component; and

forming a metallurgical bond by maintaining a compressive force of between about 10 psi and about 30 psi along an interface between the metal base of the subassembly and the metal substrate component and diffusion bonding the metal base of the subassembly and the metal substrate component to form an implant.

16. The method for preparing an implant according to claim 15, wherein the spacing agent is selected from the group consisting of hydrogen peroxide, urea, ammonium bicarbonate, ammonium carbonate, ammonium carbamate, calcium hydrogen phosphate, naphthalene, and mixtures thereof.

17. The method for preparing an implant according to claim 16, wherein the spacing agent comprises ammonium bicarbonate.

18. The method for preparing an implant according to claim 15, wherein the non-polar liquid binder is a volatile compound having a boiling point within about 100°

C. or less to the sublimation or decomposition temperature of the spacing agent.

19. The method for preparing an implant according to claim 18, wherein the removing removes both the binder and the spacing agent.